The method of preparing it, is to burn it, enclosed in a coat of cow-dung, in a furnace; which done, it is quenched with woman’s milk, and pounded with rain-water in a mortar. While this is doing, the thick and turbid part is poured off from time to time into a copper vessel, and purified with nitre. The lees of it, which are rejected, are recognized by their being full of lead and falling to the bottom. The vessel into which the turbid part has been poured off, is then covered with a linen cloth and left untouched for a night; the portion that lies upon the surface being poured off the following day, or else removed with a sponge. The part that has fallen to the bottom of the vessel is regarded as the choicest part, and is left, covered with a linen cloth, to dry in the sun, but not to become parched. This done, it is again pounded in a mortar, and then divided into tablets. But the main thing of all is, to observe such a degree of nicety in heating it, as not to let it become lead. Some persons, when preparing it on the fire, use grease instead of dung. Others, again, bruise it in water and then pass it through a triple strainer of linen cloth; after which, they reject the lees, and pour off the remainder of the liquid, collecting all that is deposited at the bottom, and using it as an ingredient in plasters and eye-salves.
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CHAP. 35.
THE SCORIA OF SILVER. SIX REMEDIES DERIVED FROM IT.
The scoria of silver is called by the Greeks “helcysma.” It has certain restringent and refrigerative effects upon bodies, and, like molybdæna, of which we shall make further mention when speaking of lead, is used as an ingredient in making plasters, those more particularly which are to promote the cicatrization of wounds. It is employed also for the cure of tenesmus and dysentery, being injected in the form of a clyster with myrtle-oil. It forms an ingredient, too, in the medicaments known as “liparæ,” for the removal of fleshy excrescences in sores, ulcerations arising from chafing, or running ulcers on the head.
The same mines also furnish us with the preparation known as “scum of silver.” There are three varieties of it; the best, known as “chrysitis;” the second best, the name of which is “argyritis;” and a third kind, which is called “molybditis.” In most instances, too, all these tints are to be found in the same cake.
The most approved kind is that of Attica; the next being that which comes from Spain. Chrysitis is the produce of the metallic vein, argyritis is obtained from the silver itself, and molybditis is the result of the smelting of lead, a work that is done at Puteoli; to which last circumstance, in fact, molybditis owes its name. All these substances are prepared in the following manner: the metal is first melted, and then allowed to flow from a more elevated receiver into a lower. From this last it is lifted by the aid of iron spits, and is then twirled round at the end of the spit in the midst of the flames, in order to make it all the lighter. Thus, as may be easily per- ceived from the name, it is in reality the scum of a substance in a state of fusion — of the future metal, in fact. It differs from scoria in the same way that the scum of a liquid differs from the lees, the one being an excretion thrown out by the metal while purifying itself, the other an excretion of the metal when purified.
Some persons distinguish two kinds of scum of silver, and give them the names of “scirerytis” and “peumene; a third variety being molybdæna, of which we shall have to make further mention when treating of lead. To make this scum fit for use, the cakes are again broken into pieces the size of a hazel-nut, and then melted, the fire being briskly blown with the bellows. For the purpose of separating the charcoal and ashes from it, it is then rinsed with vinegar or with wine, and is so quenched. In the case of argyritis, it is recommended, in order to blanch it, to break it into pieces the size of a bean, and then to boil it with water in an earthen vessel, first putting with it, wrapped in linen cloths, some new wheat and barley, which are left there till they have lost the outer coat. This done, they bruise the whole in mortars for six consecutive days, taking care to rinse the mixture in cold water three times a day, and after that, in an infusion of hot water and fossil salt, one obolus of the latter to every pound of scum: at the end of the six days it is put away for keeping in a vessel of lead.
Some persons boil it with white beans and a ptisan of barley, and then dry it in the sun; others, again, with white wool and beans, till such time as it imparts no darkness to the wool; after which, first adding fossil salt, they change the water from time to time, and then dry it during the forty hot- test days of summer. In some instances the practice is, to boil it in water in a swine’s paunch, and then to take it out and rub it with nitre; after which, following the preceding method, they pound it in a mortar with salt. Some again never boil it, but pound it only with salt, and then rinse it with water.
Scum of silver is used as an ingredient in eye-salves, and, in the form of a liniment, by females, for the purpose of removing spots and blemishes caused by scars, as also in washes for the hair. Its properties are desiccative, emollient, refrigerative, temperative, and detergent. It fills up cavities in the flesh produced by ulceration, and reduces tumours. For all these purposes it is employed as an ingredient in plaster, and in the liparæ previously mentioned. In combination with rue, myrtle, and vinegar, it removes erysipelas: and, with myrtle and wax, it is a cure for chilblains.
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CHAP. 36. (7.)
MINIUM: FOR WHAT RELIGIOUS PURPOSES IT WAS USED BY THE ANCIENTS.
It is also in silver-mines that minium is found, a pigment held at the present day in very high estimation; and by the Romans in former times not only held in the highest estimation, but used for sacred purposes as well. Verrius enumerates certain authors, upon whose testimony we find it satisfactorily established that it was the custom upon festivals to colour the face of the statue of Jupiter even with minium, as well as the bodies of triumphant generals; and that it was in this guise that Camillus celebrated his triumph. We find, too, that it is through the same religious motives that it is employed at the present day for colouring the unguents used at triumphal banquets, and that it is the first duty of the censors to make a contract for painting the statue of Jupiter with this colour.
For my own part, I am quite at a loss for the origin of this usage; but it is a well-known fact, that at the present day even, minium is in great esteem with the nations of Æthiopia, their nobles being in the habit of staining the body all over with it, and this being the colour appropriated to the statues of their gods. I shall therefore use all the more diligence in enquiring into all the known facts respecting it.
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CHAP. 37.
THE DISCOVERY AND ORIGIN OF MINIUM.
Theophrastus states that, ninety years before the magistracy of Praxibulus at Athens — a date which answers to the year of our City, 439 — minium was discovered by Callias the Athenian, who was in hopes to extract gold, by submitting to the action of fire the red sand that was found in the silver-mines. This, he says, was the first discovery of minium. He states, also, that in his own time, it was already found in Spain, but of a harsh and sandy nature; as also in Colchis, upon a certain inaccessible rock there, from which it was brought down by the agency of darts. This, however, he says, was only an adulterated kind of minium, the best of all being that procured in the Cilbian Plains, above Ephesus, the sand of which has just the colour of the kermes berry. This sand, he informs us, is first ground to powder and then washed, the portion that settles at the bottom being subjected to a second washing. From this circumstance, he says, arises a difference in the article; some persons being in the habit of preparing their minium with a single washing, while with others it is more diluted. The best kind, however, he says, is that which has undergone a second washing.
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CHAP. 38.
CINNABARIS.
I am not surprised that this colour should have been held in such high esteem; for already, in the days of the Trojan War, rubrica was highly valued, as appears from the testim
ony of Homer, who particularly notices the ships that were coloured with it, whereas, in reference to other colours and paintings, he but rarely notices them. The Greeks call this red earth “miltos,” and give to minium the name of “cinnabaris,” and hence the error caused by the two meanings of the same word; this being properly the name given to the thick matter which issues from the dragon when crushed beneath the weight of the dying elephant, mixed with the blood of either animal, as already described. Indeed this last is the only colour that in painting gives a proper representation of blood. This cinnabaris, too, is extremely useful as an ingredient in antidotes and various medicaments. But, by Hercules ! our physicians, because minium also has the name of “cinnabaris,” use it as a substitute for the other, and so employ a poison, as we shall shortly show it to be.
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CHAP. 39.
THE EMPLOYMENT OF CINNABARIS IN PAINTING.
The ancients used to paint with cinnabaris those pictures of one colour, which are still known among us as “ monochromata.” They painted also with the minium of Ephesus: but the use of this last has been abandoned, from the vast trouble which the proper keeping of the picture entailed. And then besides, both these colours were thought to be too harsh; the consequence of which is, that painters have now adopted the use of rubrica and of sinopis, substances of which I shall make further mention in the appropriate places.
Cinnabaris is adulterated by the agency of goats’ blood, or of bruised sorb-apples. The price of genuine cinnabaris is fifty sesterces per pound.
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CHAP. 40.
THE VARIOUS KINDS OF MINIUM. THE USE MADE OF IT IN PAINTING.
According to Juba minium is also a production of Carmania, and Timagenes says that it is found in Æthiopia. But from neither of those regions is it imported to Rome, nor, indeed, from hardly any other quarter but Spain ; that of most note coming from Sisapo, a territory of Bætica, the mine of minium there forming a part of the revennes of the Roman people. Indeed there is nothing guarded with a more constant circumspection; for it is not allowable to reduce and refine the ore upon the spot, it being brought to Rome in a crude state and under seal, to the amount of about two thousand pounds per annum. At Rome, the process of washing is performed, and, in the sale of it, the price is regulated by statute; it not being allowed to exceed seventy sesterces per pound. There are numerous ways, however, of adulterating it, a source of considerable plunder to the company.
For there is, in fact, another kind of minium, found in most silver-mines as well as lead-mines, and prepared by the calcination of certain stones that are found mixed with the metallic vein — not the minerals, however, to the fluid humours of which we have given the name of quicksilver; for if those are subjected to the action of fire they will yield silver — but another kind of stone that is found with them. These barren stones, too, may be recognized by their uniform leaden colour, and it is only when in the furnace that they turn red. After being duly calcined they are pulverized, and thus form a minium of second-rate quality, known to but very few, and far inferior to the produce of the native sand that we have mentioned. It is with this substance, then, as also with syricum, that the genuine minium is adulterated in the manufactories of the company. How syricum is prepared we shall describe in the appropriate place. One motive, however, for giving an under-coat of syricum to minium, is the evident saving of expense that results therefrom. Minium, too, in another way affords a very convenient opportunity to painters for pilfering, by wash- ing their brushes, filled with the colouring matter, every now and then. The minium of course falls to the bottom, and is thus so much gained by the thief.
Genuine minium ought to have the brilliant colour of the kermes berry; but when that of inferior quality is used for walls, the brightness of it is sure to be tarnished by the moisture, and this too, although the substance itself is a sort of metallic mildew. In the mines of Sisapo, the veins are composed exclusively of the sandy particles of minium, without the intermixture of any silver whatever; the practice being to melt it like gold. Minium is assayed by the agency of gold in a state of incandescence: if it has been adulterated, it will turn black, but if genuine, it retains its colour. I find it stated also that minium is adulterated with line; the proper mode of detecting which, is similarly to employ a sheet of red hot iron, if there should happen to be no gold at hand.
To objects painted with minium the action of the sun and moon is highly injurious. The proper method of avoiding this inconvenience, is to dry the wall, and then to apply, with a hair brush, hot Punic wax, melted with oil; after which, the varnish must be heated, with an application of gall-nuts, burnt to a red heat, till it quite perspires. This done, it must be smoothed down with rollers made of wax, and then polished with clean linen cloths, like marble, when made to shine. Persons employed in the manufactories in preparing minium protect the face with masks of loose bladder-skin, in order to avoid inhaling the dust, which is highly pernicious; the covering being at the same time sufficiently transparent to admit of being seen through.
Minium is employed also for writing in books; and the letters made with it being more distinct, even on gold or marble, it is used for the inscriptions upon tombs.
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CHAP. 41. (8.)
HYDRARGYROS. REMEDIES DERIVED FROM MINIUM.
Human industry has also discovered a method of extracting hydrargyros from the inferior minium, a substitute for quick-silver, the further mention of which was deferred, a few pages before, to the present occasion. There are two methods of preparing this substance; either by pounding minium and vinegar with a brazen pestle and mortar, or else by putting minium into flat earthen pans, covered with a lid, and then enclosed in an iron seething-pot well luted with potter’s clay. A fire is then lighted under the pans, and the flame kept continually burning by the aid of the bellows; which done, the steam is carefully removed, that is found adhering to the lid, being like silver in colour, and similar to water in its fluidity. This liquid, too, is easily made to separate in globules, which, from their fluid nature, readily unite.
As it is a fact generally admitted, that minium is a poison, I look upon all the recipes given as highly dangerous which recommend its employment for medicinal purposes; with the exception, perhaps, of those cases in which it is applied to the head or abdomen, for the purpose of arresting hæmorrhage, due care being taken that it is not allowed to penetrate to the viscera, or to touch any sore. Beyond such cases as these, for my own part, I should never recommend it to be used in medicine.
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CHAP. 42.
THE METHOD OF GILDING SILVER.
At the present day silver is gilded almost exclusively by the agency of hydrargyros; and a similar method should always be employed in laying gold leaf upon copper. But the same fraud which ever shows itself so extremely ingenious in all departments of human industry, has devised a plan of substituting an inferior material, as already mentioned.
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CHAP. 43.
TOUCHSTONES FOR TESTING GOLD.
A description of gold and silver is necessarily accompanied by that of the stone known as “coticula.” In former times, according to Theophrastus, this stone was nowhere to be found, except in the river Tmolus, but at the present day it is found in numerous places. By some persons it is known as the “Heraclian,” and by others as the “Lydian” stone. It is found in pieces of moderate size, and never exceeding four inches in length by two in breadth. The side that has lain facing the sun is superior to that which has lain next to the ground. Persons of experience in these matters, when they have scraped a particle off the ore with this stone, as with a file, can tell in a moment the proportion of gold there is in it, how much silver, or how much copper; and this to a scruple, their accuracy being so marvellous that they are never mistaken.
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CHAP. 44.
T
HE DIFFERENT KINDS OF SILVER, AND THE MODES OF TESTING IT.
There are two kinds of silver. On placing a piece of it upon an iron fire-shovel at a white heat, if the metal remains perfectly white, it is of the best quality: if again it turns of a reddish colour, it is inferior; but if it becomes black, it is worthless. Fraud, however, has devised means of stultifying this test even; for by keeping the shovel immersed in men’s urine, the piece of silver absorbs it as it burns, and so displays a fictitious whiteness. There is also a kind of test with reference to polished silver: when the human breath comes in contact with it, it should immediately be covered with steam, the cloudiness disappearing at once.
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CHAP. 45. (9.)
MIRRORS.
It is generally supposed among us that it is only the very finest silver that admits of being laminated, and so converted into mirrors. Pure silver was formerly used for the purpose, but, at the present day, this too has been corrupted by the devices of fraud. But, really, it is a very marvellous property that this metal has, of reflecting objects; a property which, it is generally agreed, results from the repercussion of the air, thrown back as it is from the metal upon the eyes. The same too is the action that takes place when we use a mirror. If, again, a thick plate of this metal is highly polished, and is rendered slightly concave, the image or object reflected is enlarged to an immense extent; so vast is the difference between a surface receiving, and throwing back the air. Even more than this-drinking-cups are now made in such a manner, as to be filled inside with numerous concave facets, like so many mirrors; so that if but one person looks into the interior, he sees reflected a whole multitude of persons.
Delphi Complete Works of Pliny the Elder Page 234
